I got it to work... I don't know how. I ran Windows in safe mode and solidworks wouldn't open because it couldn't check the license, i ran it in network mode and it just wouldn't open, then I tried it again in normal and it started working... Odd.

The only thing is it won't let me change the dims as I select them, I have to click into the Smart dimension to edit it.Also I now need to name the Dim before I can give it's value (see pic), this is very frustrating as I'm used to being able to quickly change the dim in SW2016, do you have any idea of how i can change this?

Had the same problem and was working the issue for hours looking through tons of forum posts.

Turns out the issue is that the FONT for the dimension text is not being registered.

Go to Open an Empty Part, Then go to: Options > Document Properties > Dimensions (the main one not any of the sub-options) and click on the [Font...] Button underneath the Text area. And change your font to a more common one like Arial, Times, etc.

To check go to a Dimensions sub-option; such as Diameter, Hole Callout, Linear, etc. One that shows a "preview" of what your dimension would look like. If it is now visible then you should be able to use Smart Dimension once again.

Make sure you go to [Save As], and save as a Part Template so that you can use your new fixed template (or overwrite to corrupted one)

The key thin here, is that you can use the Dimensions Sub-options preview windows to check which Fonts are accessible to Solidworks. As if you cant see any dimension in the preview or it doesnt look right; then your Smart Dimensions will fail in the manner you and I experienced.

For me it was the Century Gothic Font that caused this. It may be different for you.

And just to be clear.

THE ONLY THING I CHANGED WAS THE FONT EVERYTHING ELSE WAS DEFAULTS FROM A REINSTALL.